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I thought that microprocessor production and design was fraught with risk of infringing on other designers' patents (even for original ISAs). I can see that in

I thought that microprocessor production and design was fraught with risk of infringing on other designers' patents (even for original ISAs). I can see that industry heavyweights have arrived to support RISC-V, so hopefully that comes with a team of professors/lawyers that could defend them. But, why now? Why couldn't this have happened sooner? Didn't Sun try to create an open SPARC processor design? What does RISC-V have that it didn't? Is the intent for RISC-V to compete with modern high-end CPU designs, or do we just want to have royalty-free microprocessors for our embedded devices? You might be surprised (at least I was) to learn that peripherals like hard drives and PCI-add-in cards usually have their own CPU executing their own software. Those processors are often MIPS/ARM/etc based and the manufacturer has to shell out to someone to be able to use that, even if they designed the processor themselves. I can see how this particular market is ripe for something like RISC-V. But does anyone expect RISC-V to really go head-to-head with Xeon, Opteron, ThunderX, Centriq? I sound incredulous because this seems surprising to me, but I have no evidence to suggest whether it's as unlikely as I think. I've certainly seen open source software designs far superior to closed source ones, so maybe hardware design is no different?

microcolonel 10y ago
There are a number of things that make RISC-V different from OpenSPARC. One is that OpenSPARC is not a very scalable design, it could probably only ever work in servers and workstations, and workstations are essentially a monoculture. Another reason is timing: manufacturing processes have effectively stopped yielding performance and power gains as the fundamental constraint (distance between components on chip) doesn't get any smaller. This means that in order to keep the pace up for any popular workload, many new microarchitectures will need to be created. RISC-V is amenable to a wide array of microarchitectural decisions, and doesn't carry the architectural baggage of ARM and MIPS licensing and technical quirks, or the impossible licensing of x86. > But does anyone expect RISC-V to really go head-to-head with Xeon, Opteron, ThunderX, Centriq? Except for Intel, none of these manufacturers have any reason to resist RISC-V. All of these vendors can directly port knowledge from one ISA to another. So really it becomes a matter of "will there be a demand for RISC-V hardware in the server and workstation markets?", and the answer to that is a firm "maybe". I think that today, since most software is written in high level languages which are at least as abstract as C, there is little reason why a new ISA couldn't take hold in any of these markets if hardware vendors can promise good things to ISVs and to customers who write their own software. At present, there is a considerable barrier to entry for new designers and manufacturers to approach ARM, POWER, and MIPS, and basically no hope of manufacturing an AMD64. ARM is not the cuddly RISC architecture people think it is, it is in many ways nearly as quirky as x86, and therefore very expensive to enter and innovate on. Furthermore, it can take more than a year to negotiate an architectural license with ARM, your company or the market might no longer exist by the time you close the deal. POWER is not too far off on licensing, and it's not all that elegant either (though far more surmountable than ARM). MIPS lacks industry momentum and standardized high performance feature sets (wide vector compute, hardware security features), and its custodian company seems to barely acknowledge it exists. All in all, nobody knows if it'll work out, but there are good reasons for RISC-V to succeed in the market. The challenges also seem surmountable.
- dom0 10y ago
  OpenSPARC is GPL. And OpenSPARC means the T1/T2 designs (high throughput, very low single-threaded performance) which are useless outside their niche.
- CalChris 10y ago
  > RISC-V is amenable to a wide array of microarchitectural decisions As is ARMv8. Applied Micro, Broadcom, Cavium, Huawei, Nvidia, AMD, Samsung and Apple are all architectural licensees with radically different microarchitectural implementations. For example, Nvidia is Transmeta code-morphing style implementation. Also, Intel and AMD continue to innovate in the x86 space. At this date, RISC-V has no fundamental advantage over any of these architectures and then has the fundamental disadvantage of not having access to their IP. You're lining up against Usain Bolt and your advantage is that you're wearing organic cotton. That's just not gonna work.
  - analognoise 10y ago
    " You're lining up against Usain Bolt and your advantage is that you're wearing organic cotton. That's just not gonna work." I'm stealing this as a saying.
  - yaantc 10y ago
    You're right, but key words here are "At this date". What you said could have been said exactly in the same way about Linux against commercial Unices about 15 years ago. It's a long game here, and we're only in the early phase. And it may not take that long, but we'll see. Regarding technology, just as Linux initially the key is not having a technological advantage, but being cheaper and good enough. The improvements can come later, when the ecosystem gets bigger and more resources pours in.
    - sweden 10y ago
      RISC-V is thrown around like if it's an already working CPU but it is not. It is just a document describing an ISA, you can't compare it to Linux, it's a completely different thing. There are a lot of costs in implementing an ISA and that includes: design, functional verification, physical implementation and software testing. All those steps together will require hundreds and hundreds of engineers, many expensive tools and thousands of man-hours. And once you are done, you will need to find be careful not to violate any patents while shipping your CPU to the end customer. By paying a license fee to ARM, you get all these steps done for you plus with support. Linux is something that you can download from kernel.org, compile overnight and get it booting right away. RISC-V is something that you need to build yourself.
indolering 10y ago
The RISC-V team was very careful in establishing prior art for every design decision. The patents on ISAs tend to be on their quirks, so keeping things truly minimal helps avoid all of that complexity. Like a lot of what Sun did, prior open chip designs weren't good enough. Academics starting with a clean slate and a 20+ years of additional experience gives RISC-V real advantages over MIPS and ARM. The primary advantage is that RISC-V is truly RISC: they have a core ISA that is frozen but extendable. This means that they can have application-specific CPUs with intelligent fallback and full compatibility. As to why now, well, they came up with RISC-V as a teaching ISA and started getting emails from industry asking why it had changed from last semester. It turns out that chip manufacturing has gotten cheap, with custom runs on 28nm processes going for $30K. You are correct in that their early target market are co-processors and other niche components. Just getting a license from ARM is 10+ million dollars. But the biggest cost in building your own ISA is investment in software and tooling. RISC-V gives a common foundation for everyone to build on. However, their intent is indeed to bring competition at every level. Their licensing scheme was chosen specifically to allow big players to create IP and keep the secret sauce to themselves, unlike SPARC V8 and OpenRISC. Apple creates their own CPU and GPU designs, Google has custom hardware for machine learning, and Samsung is about to overtake Intel as the world's largest chip manufacturer. Why should they keep shelling out billions to ARM, Intel, and AMD just to use their ISA?
- dom0 10y ago
  > Just getting a license from ARM is 10+ million dollars. Which license? ARM offers several different models. > Apple creates their own CPU and GPU designs, Google has custom hardware for machine learning, and Samsung is about to overtake Intel as the world's largest chip manufacturer. Why should they keep shelling out billions to ARM, Intel, and AMD just to use their ISA? The Google hardware we know (TPU) for learning does not use ARM at all, so they would obviously pay nothing there. BigCo's like Apple or Samsung are probably ARM partners, so no per-design/unit fees. Samsung Electronics may become the biggest chip manufacturer soon, but much like with smartphones that's only by turnover, not profit. But profit is what ultimately finances your R&D. An interesting titbit is that even Intel and ARM are, at least on paper, partners.
mtgx 10y ago
> does anyone expect RISC-V to really go head-to-head with Xeon, Opteron, ThunderX, Centriq? Yes, and no. RISC-V is disruptive [1] to both ARM and x86. But before it can run (compete with Intel CPUs), it needs to crawl (compete with low-end ARM CPUs/microcontrollers). It could take a decade or more before RISC-V competes at the high-end. Basically think of it as following ARM's path but on a much more accelerated path (for many different reasons: much larger chip market these days, being open source and royalty-free, etc). [1] - https://www.youtube.com/watch?v=mbPiAzzGap0 https://www.youtube.com/watch?v=mbPiAzzGap0
- noir_lord 10y ago
  I think part of the accelerated path will be that we are reaching the limits of 'easy' (in the billions already) process improvements. When everyone and his dog has 14nm you can't rely on process to keep you ahead, Ryzen has shown this partially recently, Broadwell level IPC on an Octacore processor for less than Intel sells a Quad core. It's going to be a bloodbath as the middle eats into the top.

microcolonel 10y ago

There are a number of things that make RISC-V different from OpenSPARC. One is that OpenSPARC is not a very scalable design, it could probably only ever work in servers and workstations, and workstations are essentially a monoculture. Another reason is timing: manufacturing processes have effectively stopped yielding performance and power gains as the fundamental constraint (distance between components on chip) doesn't get any smaller. This means that in order to keep the pace up for any popular workload, many new microarchitectures will need to be created. RISC-V is amenable to a wide array of microarchitectural decisions, and doesn't carry the architectural baggage of ARM and MIPS licensing and technical quirks, or the impossible licensing of x86. > But does anyone expect RISC-V to really go head-to-head with Xeon, Opteron, ThunderX, Centriq? Except for Intel, none of these manufacturers have any reason to resist RISC-V. All of these vendors can directly port knowledge from one ISA to another. So really it becomes a matter of "will there be a demand for RISC-V hardware in the server and workstation markets?", and the answer to that is a firm "maybe". I think that today, since most software is written in high level languages which are at least as abstract as C, there is little reason why a new ISA couldn't take hold in any of these markets if hardware vendors can promise good things to ISVs and to customers who write their own software. At present, there is a considerable barrier to entry for new designers and manufacturers to approach ARM, POWER, and MIPS, and basically no hope of manufacturing an AMD64. ARM is not the cuddly RISC architecture people think it is, it is in many ways nearly as quirky as x86, and therefore very expensive to enter and innovate on. Furthermore, it can take more than a year to negotiate an architectural license with ARM, your company or the market might no longer exist by the time you close the deal. POWER is not too far off on licensing, and it's not all that elegant either (though far more surmountable than ARM). MIPS lacks industry momentum and standardized high performance feature sets (wide vector compute, hardware security features), and its custodian company seems to barely acknowledge it exists. All in all, nobody knows if it'll work out, but there are good reasons for RISC-V to succeed in the market. The challenges also seem surmountable.

dom0 10y ago
OpenSPARC is GPL. And OpenSPARC means the T1/T2 designs (high throughput, very low single-threaded performance) which are useless outside their niche.
CalChris 10y ago
> RISC-V is amenable to a wide array of microarchitectural decisions As is ARMv8. Applied Micro, Broadcom, Cavium, Huawei, Nvidia, AMD, Samsung and Apple are all architectural licensees with radically different microarchitectural implementations. For example, Nvidia is Transmeta code-morphing style implementation. Also, Intel and AMD continue to innovate in the x86 space. At this date, RISC-V has no fundamental advantage over any of these architectures and then has the fundamental disadvantage of not having access to their IP. You're lining up against Usain Bolt and your advantage is that you're wearing organic cotton. That's just not gonna work.
- analognoise 10y ago
  " You're lining up against Usain Bolt and your advantage is that you're wearing organic cotton. That's just not gonna work." I'm stealing this as a saying.
- yaantc 10y ago
  You're right, but key words here are "At this date". What you said could have been said exactly in the same way about Linux against commercial Unices about 15 years ago. It's a long game here, and we're only in the early phase. And it may not take that long, but we'll see. Regarding technology, just as Linux initially the key is not having a technological advantage, but being cheaper and good enough. The improvements can come later, when the ecosystem gets bigger and more resources pours in.
  - sweden 10y ago
    RISC-V is thrown around like if it's an already working CPU but it is not. It is just a document describing an ISA, you can't compare it to Linux, it's a completely different thing. There are a lot of costs in implementing an ISA and that includes: design, functional verification, physical implementation and software testing. All those steps together will require hundreds and hundreds of engineers, many expensive tools and thousands of man-hours. And once you are done, you will need to find be careful not to violate any patents while shipping your CPU to the end customer. By paying a license fee to ARM, you get all these steps done for you plus with support. Linux is something that you can download from kernel.org, compile overnight and get it booting right away. RISC-V is something that you need to build yourself.

indolering 10y ago

The RISC-V team was very careful in establishing prior art for every design decision. The patents on ISAs tend to be on their quirks, so keeping things truly minimal helps avoid all of that complexity. Like a lot of what Sun did, prior open chip designs weren't good enough. Academics starting with a clean slate and a 20+ years of additional experience gives RISC-V real advantages over MIPS and ARM. The primary advantage is that RISC-V is truly RISC: they have a core ISA that is frozen but extendable. This means that they can have application-specific CPUs with intelligent fallback and full compatibility. As to why now, well, they came up with RISC-V as a teaching ISA and started getting emails from industry asking why it had changed from last semester. It turns out that chip manufacturing has gotten cheap, with custom runs on 28nm processes going for $30K. You are correct in that their early target market are co-processors and other niche components. Just getting a license from ARM is 10+ million dollars. But the biggest cost in building your own ISA is investment in software and tooling. RISC-V gives a common foundation for everyone to build on. However, their intent is indeed to bring competition at every level. Their licensing scheme was chosen specifically to allow big players to create IP and keep the secret sauce to themselves, unlike SPARC V8 and OpenRISC. Apple creates their own CPU and GPU designs, Google has custom hardware for machine learning, and Samsung is about to overtake Intel as the world's largest chip manufacturer. Why should they keep shelling out billions to ARM, Intel, and AMD just to use their ISA?

dom0 10y ago
> Just getting a license from ARM is 10+ million dollars. Which license? ARM offers several different models. > Apple creates their own CPU and GPU designs, Google has custom hardware for machine learning, and Samsung is about to overtake Intel as the world's largest chip manufacturer. Why should they keep shelling out billions to ARM, Intel, and AMD just to use their ISA? The Google hardware we know (TPU) for learning does not use ARM at all, so they would obviously pay nothing there. BigCo's like Apple or Samsung are probably ARM partners, so no per-design/unit fees. Samsung Electronics may become the biggest chip manufacturer soon, but much like with smartphones that's only by turnover, not profit. But profit is what ultimately finances your R&D. An interesting titbit is that even Intel and ARM are, at least on paper, partners.

mtgx 10y ago

> does anyone expect RISC-V to really go head-to-head with Xeon, Opteron, ThunderX, Centriq? Yes, and no. RISC-V is disruptive [1] to both ARM and x86. But before it can run (compete with Intel CPUs), it needs to crawl (compete with low-end ARM CPUs/microcontrollers). It could take a decade or more before RISC-V competes at the high-end. Basically think of it as following ARM's path but on a much more accelerated path (for many different reasons: much larger chip market these days, being open source and royalty-free, etc). [1] - https://www.youtube.com/watch?v=mbPiAzzGap0 https://www.youtube.com/watch?v=mbPiAzzGap0

noir_lord 10y ago
I think part of the accelerated path will be that we are reaching the limits of 'easy' (in the billions already) process improvements. When everyone and his dog has 14nm you can't rely on process to keep you ahead, Ryzen has shown this partially recently, Broadwell level IPC on an Octacore processor for less than Intel sells a Quad core. It's going to be a bloodbath as the middle eats into the top.